Air-warming furnace



(N0 Moder. -3 Sheets-Shet 1.

G. W. JOHNSTQN. AIR WARMING FURNACE. I

No]. 501,604.. Patented July 18, 1 893..

irizjwssz'sl (No Model.) 3 Sheets-Sheet 2.

W JOHNSTON. AIR WARMING FURNACE.

No..501,604." 1 PatentedJuly18,1893.

(No Model.) a Shets-Sheet s.

' G. W. JOHNSTON.

4 'AIR WARMING FURNACE. N0.501,604 Patented July 18,1893.

Z WZZWESSES STATES PATENT FFIQE.

AIR-WARMING FU RNACE.

$PECIFIGATION forming part of Letters Patent No. 501,604, dated July 18, 1893.

Application filed March 13, 1293- Serial No. 465,777. (No model.)

To all whom it may concern.

Be it known that I, GEORGE W. JOHNSTON, acitizen of the United States, and a resident in the town of Farmington, in the county of Fulton, in the State of Illinois, have invented a new and useful AirWarming Furnace, of which the following is a correct description.

The invention relates to that class of heating devices in which the furnace or fuel and combustion-chamber, proper, is iuclosed Within a jacket or casing,which has air-inlet openings and air-outlet passages,in such a manner that the space between the furnace 'and the jacket, constitutes a reservoir of warmed air, from which, through the air-outlet passages, the various apartments above the basement,in which, ordinarily,the furnace is located,are supplied with pure atmospheric air, of any desired temperature.

The leading object of the invention is to provide in an air-warming furnace, appliances whereby thorough utilization of the heat-producing properties of the fuel shall be insured. This is accomplished through the provision of air-warming chambers or passages, of such configuration, and in such location, relatively to the combustion-chamber and to the fuelchamber of the apparatus, that the currents of air introduced through such chambers or passages, shall, as they issue therefrom, be of such temperature,as they meet and mingle with the gases evolved through combustion of the fuel,as to insure the complete combustion thereof, and the consequent thorough utilization of all the valuable properties of the fuel. This object is further promoted, and its accomplishment more certainly insured, through the provision instead of the thick and heavy cast or wrought metal cylinder and dome of the combustion-chamber of the furnace, as usually employed, of a cylinder and dome of sheet-metal; and it is additionally insured through the provision of a flue-system in the operation of which the volatile products of combustion are carried downward in two currents, or in a divided current which underlies the ash-pit chamber, and overspreads the entire base section of the furnace, and reaches the rear thereof through two distinct and independent horizontal basefines.

The inventionconsists in various novel elements or combinations of elements in an airwarming furnace, as will appear from the following detailed description, and from the specific and distinct claims which succeed such description.

In the accompanying drawings, which constitute a part of this specification-Figure 1 represents a front perspective elevation of the furnace. Fig. 2 is a longitudinal vertical section, in a plane partially central of the furnace, and partially in a plane at a short distance from the center. Fig. 3 is a transverse central section of the furnace. Fig. 4 is a top plan view of the smoke-box and radiator. Fig. 5 is a bottom plan view of the smoke-box and radiator. Fig. 6 is a sectional plan view, in the line x-x of Fig. 2. Fig. 7 is a sectional plan, in the irregular line 1 1 of Fig. 2. Fig.8 is a vertical section in the irregular plane indicated by the line z-z in Fig. 2.

The base-plate B, of the furnace A is, in its outer portion, formed with a peripheral downwardly and outwardly extending flange b, which at its top is provided with a groove b and at its foot with a rim Iii-which latter receives the lower extremity of the jacket or casing O,both casing and flange being provided with necessary openings to permit inflow of air tot he reservoir or hot-air chamber, and to the air-conducting pipes of the radiator or smoke-box.

The vertical lower portion of the body A of the furnace rests, by its lower extremity, in the groove or channel I) of the base-plate; and at a point in a plane somewhat below the upper extremity of the fire-pot, is upwardly indrawn, and curved, to form a dome-like overhang a, upon the upper extremity of which rests the cylindrical body or shell a of the combustion-chamber a of the furnace.

At a short distance above the base-plate B, and parallel therewith, is the ash-pit or ashchamber plate a, which in its central portion rests upon a vertical division-plate a which extends from front to rear of the furnace, and separates the two right and left'baseflues a and a The ash-pan or ash-drawer A rests upon the central or intermediate portion of the supporting plate of, ard is withdrawable bodily from its seat thereon, through the opening which is closed by the door a cl.

Immediately above the plane of the ashdrawer chamber is the an nular plate a within the open portion of which is supported a flaring fire-pot or fuel-chamber a, and, in connection therewith, any suitable grate or gratebars g.

Within the lower and central portions of the cylindrical combustion-chamber (t of the furnace, is a deflecting-cylinder a, which at its upper extremity has an outwardly-projecting flange or rim of, which at this point closes the narrow space between the two cylinders, and which extends perpendicularly downward to a point slightly below the plane of the upper extremity of the dome-like portion or overhang a, where it depends, curtainlike, to a point near the upper extremity of the fire-pot or fuel-receptacle a".

In a plane at about the midheight of the deflecting-cylinder a ,openings, at suitable intervals, in the body or shell of the combustion-chamber, and in the body of the air-casing or jacket, are connected by corresponding air-inlet pipes at p, which, in practice, are at their outer extremity, provided with a register-damper, or other suitable means for total or partial exclusion of air.

At a point somewhat below the plane of the series of air-inlet pipes a p, are horizontal airinlet pipes Ct i,one at each side of the feedchutef c,and if desired, at other points in the same horizontal plane. The pipes az'extend inwardly as shown, from the air-casing to a point near the wall or shell of the combustion-chamber, at which they are curved, and from which they extend upwardly, to the top of the furnace, across or partially across which they extend, and are connected to suitable openings (1 0, through which the currents of air, introduced at the outer extremity of the pipes, find entrance into the upper extremity of the combustion-chamber5-as represented in Figs. 2 and 3.

At the rear upper portion of the combustion-chamber (see Fig. 2), a smoke-exit opening 6 0, a horizontal, rearwardly-extending exit-pipe e p, and a damper d are provided; while coincident therewith, at the front, in a slightly lower plane, is the fuel-supply passage or feed-chute f c.

Extending vertically upward from the ashchamber plate a, are the smoke-conducting pipes s and 3 which correspond respectively with the right and left base-tines a and a The fines or pipes s and 8 extending vertically upward, as stated, are connected at their upper extremity to the lower extremity of the smoke-box or radiator R, which is in plane with the combustion-chamber of the furnace, and in a horizontal plane is of the segmental or crescent form seen inFigs. 4 and 5. At its upper extremity a central discharging-pipe '1', connects it with the horizontal exit-pipe 619, at a point in rear of the damper d; and in its intermediate portions, between the planes of the pipes s and s and the central discharge-pipe r, it is provided with the vertically-extending air-conducting pipes r 4' and r 7*.

To persons skilled in theart to which the invention relates, the operation of the apparatus will, in the main, be clearly apparent from the illustration thereof in the drawings, and from the foregoing description.

Fuel being suitably supplied and ignited, and the damper in the direct-exit pipe being opened, air admitted under the grate, through the draft-openings in the doorad, of the ashchamber, will quickly cause active combustion of the fuel. This being thoroughly es-- tablished, the directexit passage will be closed, and the course of the volatile products of combustion will thenceforward be downward at the f ron t-but partly upon each quarter of the fire-pot,to and through the openings 0 and 0 in the annular supportingplate a and to and through the openings 0 and 0 in the ash-chamber plate a", into the right and left base-flues a and a ,-through such base-fines to the vertically-placed pipes s and 5 through the pipes s and .9 into the smoke-box or radiator R, and through the radiator R,and its connecting-pipe 0', into and through the exit-pipe 6 It should be understood that the fresh thoroughly-oxygenated air, introduced through the series of pipes cap, will be quickly and highly heated in the thin annular chamber 0, which interiorly is exposed to the high temperature of the combustion-chamberpand that in this condition, it will be exactly adapted, as it is discharged from the lower extremityof its chamber, to meet and mingle with, and insure the thorough combustion of all the light carbonaceous matters, and all the inflammable gases evolved from the fuel, as they are car ried by the force of the draft, from the inner portion of the fuel-chamber, to the upper and outer extremity thereof, in their passage to the exit-pipe. This is especially ad vantageous in the consumption of bituminous coals,- in which the proportions of carbon and of light, combustible gases are large; and which in great part escape uncousu med, under most constructions. Through the provision of the air-induction pipes at 'i, such light combustible substances, and such gases, as may reach the upper portion of the combustion-chamber, will be met therein by the incoming air-currents, and mingling with the oxygen thereof, will be utilized as fuel. Through the described system of diving-fines and base-fines, under which, in all ordinary circumstances, the draft is indirect, the flow of the volatile currents is steady and regular, and an equable distribution of the heat, through every portion of the furnace is insured,the lower or base-section thereof receiving its full proportion. It will be observed that through the location of the vertical smoke-conducting pipes s and in plane with the outer extremity of the curved smoke-box or radiator It, and through the location ot the discharging pipe 0 at the center IlO of such radiator, the currents of smoke which are discharged into the radiator from such vertical pipes, are caused to pass transversely of the two pairs,r and r and r and r ,of intermediate vertical air-pipes,enveloping the same on all sides, and imparting to the currents of air passing therethrough, nearly their own temperature.

Th rough the substitution for the heavy cast or wrought metal furnace-body, ordinarily employed, of the thin sheet-metal upper and lower cylinders which are provided in this construction, a reservoir of warm air is much more quickly produced,the comparatively thin sheet-metal receiving and imparting the heat-particles with great rapidity.

Through the provision of the double-walled air-casing or jacket, and the non-conducting air-space between the two walls, undue heating of the apartment in which the furnace is situated is avoided, and the heat which would thus be conveyed away and wasted, is retained, for transmission to the upper stories of the structure.

It will be apparent that the advantages arising from the divided down-draft and double or twin base-flue construction, and from the smoke-box or radiator, which receives the smoke-currents at each end of its horizontallycurved chamber, and discharges them at its central or mid-length and upper extremity, are fully available independently of the presence of the air-casing or jacket.

I-am aware that in a magazine-stove a combustion-sleeve has been applied around the lower extremity-of the magazine to introduce air into the center of a combustion-chamber; but I believe that I am the first to provide within the cylindrical body or shell of an airwarming furnace, a slightly smaller cylinder which is closed at its top, at a distance below the upper extremity of the body or shell, and which forms in connection with such body or shell, a thin annular air-induction chamber which is supplied with air through pipes which extend from apoint outside the exterior casing of the furnace, into and through the hot-air chamber, and through the body or shell of the furnace. It is also known to me that in a magazine hot-air furnace, an airpipe has been extended horizontally into the combustion-chamber, and to the lower extremity of the magazine, thence upward along the rear exterior surface of the magazine, to a perforation in its wall, near the top thereof, through which its air is discharged'for the purpose of forcing accumulations of gases, in

the magazine, downwardly through the same,

and out therefrom to a point in the combustion-chamber where they may be consumed. I believe however, that I am the first to provide in an air-warming furnace, air-inlet passages which extend fromthe air-casing of the furnace, horizontally inward, through the airwarming chamber to a point near the body of the combustion-chamber, thence upwardly along the outer surface of the combustion- .chamber, tothe top thereof, thence along the top of the furnace, and across, or partially under some circumstances may be used as a combustion-chamber, has been inclosed by a cylinder of sheet-metal,the air-warming chamber of such furnace being also inclosed by a single sheet of sheet-metal. In another furnace, a portion of the air-easing hasbeen composed of two sheets of thin metal, which inclose a thin air-space;-the upper and more rapidly radiating portion of the casing being composed of a single sheet; and the combustion-chamber of the furnace being composed of cast-metal. It is my belief, however, that I am the first to combine in a single structure, a heater the walls of the fuel-chamber or firepot section and of the combustion-chamber section of which are composed of a single thickness of thin sheet-metal; and an air-casing or jacket which is composed, throughout, of double parallel walls of like sheet-metal, and an intermediate thin closed non-conducting, air-chamber.

It will be understood that I make no claim, broadly, to a means for introducing fresh air into a combustion-charmhen-either at a point nearthe upper extremity of the fuel-chamber,

or elsewhere; to a means for introducing air '1. An air-warming furnace in which are combined a fuel chamber; a combustionchamber the lower extremity of which is in near proximity to the upper extremity ofthe fuel-chamber; a deflecting-cylinder, within the cylinder of the combustion-chamber, and forming in connection therewith a thin annular air-induction chamber which is open at its lower and closed at its upper extremity;

and a series of air-pipes or passages'which.

extend from the air-casing and through-the air chamber of the furnace, to the thin annular chamber within the combustion-chamber;

whereby currents of fresh highly-heated air are supplied to the open space which is coincident with the lowerextremity of the body of the combustion-chamber,andwith the .up-

per extremity of the fuel-chamber.

2. In an air-warming furnace, a fuel-chamber or fire-pot; a combustion-chambenthe lower extremityof which is in close proximity to the upper extremity of the fuel-chamber or fire-pot; and air-induction passages which extend from the air-casing of the furnace, horizontally inward through the airwarming chamber to a point near the body of the combustion -chamber,-thence upwardly, along the ontersurfaceof the combustion-chamber, to the top thereof,thence along the top of the furnace and across or partially across the same, to an opening therein, through which air is discharged into the upper extremity of the combustion chamber; substantially as and for the purposes set forth.

3. In an air-warming furnace,a combustionchamber the lower extremity of which is in near proximity to the upper extremity of the fuel-chamber; a thin annular air-induction chamber, within the lower and middle portion of the combustion-chamber; a series of air-induction tlues which lead from a point outside the air-casing of the furnace into such thin annular air-induction chamber; and a series of air-induction flues which lead from the air-casing of the furnace inwardly to the body of such combustion chamber,upwardly along such body to the upper extremity thereof, and thence along and overlying the top of such body, to an opening therein through which air is discharged directly into the upper extremity of the combustion-chamber,in combination; substantially as and for the purposes specified.

4. In an air-warming furnace, an annular supporting-plate, in a horizontal plane immediately above the ash-chamber of the furnace, and having in its front portion a left smokeopening and a right smoke-opening; a firepot or fuel chamber, resting by its lower extremity in the opening of such annular supporting-plate; independent left and right horizontal smoke-passages, in the base of the furnace, below the ash-chamber of the sa me; an ash-chamber in which a left and a right smoke-opening are provided in the front portion of the bottom-plate of the chamber; and a smoke-box or radiator, in rear of the combustion-chamber of the furnace, which receives the products of combustion from both of the horizontal smoke-passages, and discharges the same into the single exit-pipe of the furnace,-in combination; substantially as described and shown.

5. In an air-Warming furnace, an outstanding fuel-chamber or fire-pot; combined with independent left and right base-fines, below the ash-chamber of the furnace, and overspreading the bottom surface of the same; a smoke-box or radiator, in rear of the combustion-chamber of the furnace, provided with vertical airpipes, and with a central top smoke-opening; and vertical smoke-fines one of which extends from the rear portion of each of the independent base-fines to one extremity of the smoke-box or radiatory whereby the Volatile products of combustion are caused to pass in opposite directions, within the body of the radiator.

6. In an air-warming furnace, a heater the walls of the fuel-chamber or fire-pot section and of the combustion -chamber section of which are composed of a single thickness of thin sheet-metal, to insure quick heating of the same, and rapid radiation therefrom; In combination with an air casing or jacket which is composed throughout of double parallel walls of like thin sheet metal and an 1 ntermediate thin closed non-conducting arrchamber, to insure retention of the heat within the air-reservoir of the furnace, and to permit the same to be conveyed to the apartments which are to be warmed.

7. In an air-warming furnace, a heater the walls of the fuel-chamber or fire-pot section and of the combustion-chamber section of which are composed of a single thickness of thin sheet-metal, to insure quick heating of the same, and rapid radiation therefrom, and in which the products of combustion ordinarily pass from the front upper extremity of the fuel chamber, downwardly, into and through tines in the base thereof; in combination with an air-casing or jacket which from bottom to top is composed of double parallel walls, of like thin sheet metal, embracing an intermediate thin closed non-conducting airchamber, to insure retention of the heat, within the air-reservoir of the furnace, and to permit the same to be conveyed to the apartments which are to be warmed.

8. In an air-warming furnace, a combustion-chamber which is provided in its middle and lower portion with a cylindrical deflecting sheet which forms, in connection with the wall of the combustion-chamber, an air-induction chamber or flue which is in communication with a source of fresh air, and which in its rear upper portion is provided with a dampered direct-exit pipe; combined with an isolated or outstanding fuel-chamber, below the plane of the shell of the combustion-chamber; horizontal plates which constitute the top and bottom of the ash-chamber, each provided with aleft smoke-opening and a right smoke-opening; left and right smoke-fines, beneath the ash-chamber, extending from the front of the base portion of the furnace to apoint in rear of the same; vertical smoke-passages which extend upwardly from the rear extremity of the underlying left and right smoke-fines; and a smoke-box or radiator, behind the combustion-chamber of the furnace, which receives the smoke-currents from the vertical smokepassages, and discharges the same, through a single outlet, into the dampered direct-exit pipe; substantially as specified.

In testimony whereof I hereunto set my hand, this 13th day of February, 1893, in the presence of two subscribing witnesses.

GEORGE \V. JOHNSTON.

Witnesses:

F. E. CRANE, J. L, KEELING. 

